The growing number of recipients of artificial heart valves draws ever more frequent attention to the problem of anticoagulant therapy, not only in its daily management but also in the event of specific conditions such as pregnancy, extra-cardiac surgery and invasive cardiac procedures in which specific measures must be adopted. In each case it is necessary to take into account not only the characteristics of the individual prosthesis but also those of the individual patient, each time making an overall assessment of the specific thromboembolic risk without forgetting possible complications of hemorrhage. This review examines the various mechanisms underlying the thromboembolic risk and, in the light of the leading literature on the topic, seeks to identify the most appropriate behaviors to adopt in the management of each individual case.